Patent GB-376316-A (GB)
Title: Improvements in automatic firearms
IPC: F41A3/68
Filed: 1931-01-02
Abstract: 376,316. Automatic firearms. WHITE AUTOMATIC GUN CORPORATION, Portland, Maine, U.S.A.-(Assignees of White, J. C. ; 28, Westland Avenue, Boston, U.S.A.) Jan. 2, 1931, No. 201. Convention date, Jan, 8, 1930. [Class 119.] An automatic gasoperated gun comprises a receiver, a breech - bolt bodily removable independently of the action-slide when a retaining means at the rear end of the receiver is displaced thereby, giving axial access to the barrel for cleaning, the breechbolt having longitudinal movement to open the breech and after the supply of a fresh Cartridge from below to close the breech, and being adapted without tilting to be locked by transversely movable members, and the said gun having an automatically actuated actionslide and means connecting the bolt and the slide at times for movement as a unit and for movement relatively to each other to effect the locking and unlocking of the bolt at other times. As shown, the breech-bolt 44 is formed with inclined grooves 49, Fig. 12, engaged by ribs 48 on longitudinally slidable action-plates 43 provided with notches 42 engaged by lugs 37, Fig. 5, on a fork 28 at the rear of the gas-piston device described in Specification 376,368 which also describes a foresight base. The action plates 43 are situated against the sides of the breech bolt between rear flanges 46 and front lugs 50, 51. The backward movement of the action plate, when the gun is fired, first causes the breech bolt to be lifted bodily to disengage the front lugs 50, 51 from interlocking abutments on the receiver 2, and then the breechbolt follows the backward and return movement of the action-plate until the breech is again closed, after which the completion of the forward stroke of the action-plate causes the breech-bolt to be lowered down bodily to bring the front lugs 50, 51 again into locking engagement with the abutments of the receiver. The end of the rearward stroke of the gas fork is cushioned by a blade spring which is wedged down by the gas fork. Fresh cartridges are fed from a magazine 110, Fig. 2, below the breech-bolt, the spent cartridges are ejected by an ejector 68, and the breech-bolt is held in the open position when the last cartridge has been fired, all as described in Specification 376,294. An extractor 64 is loosely fitted in vertical guides 66, 66 on the front face of the breech-bolt and depends from a bevelled toppiece 62 fitting in a recess 63 in the top of the breech-bolt and provided with arms 71 fitting in grooves 73 in the top of the action-plates 43. This extractor is controlled by a flat spring 74 provided with a pair of pins 77, which are fitted into holes 78 in the breech-bolt to position the spring on the breech-bolt and to retain the firing-pin 80 in the breech-bolt. The breech-bolt may also be operated by a handaction slide 99, which is provided with a handle 104 and is slidably mounted on a guide 98 on the receiver, the slide when in its forward position being also capable of being turned with the handle through about 45 to put it in or out of action When the handle is turned down, a lug 105 on the slide comes out of a recess in the receiver and unlocks the handle from the receiver ; at the same time another lug 103 on the slide comes in front of a wing 102 on a sliding link connected by a pivot to the gas fork, so that a backward pull of the handle will open the breech. The rear of the receiver is closed by a cap 87 pivoted at 88 and held in place at the rear by a catch 90 pivoted at 91 on a plate 92 and provided with a thumb-piece 95. The plate 92 is anchored to the stock 5 by a screw 96 and a bolt 97, which also secures the rear end of the guard plate 70. The barrel is covered by a separate forestook held by a strap, which also serves as a base for the shoulder-strap ring. The barrel is screwed to a bushing 9 in the front of the receiver. The barrel and the receiver can be dismounted from the stock after the removal of a screw 11 and the aforesaid strap. The hand operation of the breech mechanism, the extractor and ejector mechanism, the cartridge feed mechanism and the means for holding the breech-bolt in the open position when the last cartridge has been fired are stated to form no part of the invention. Specifitions 23387/04, 208/10, and 156,541, [all in Class 119, Smallarms], also are referred to. The Specification as open to inspection under Sect. 91 (3) (a) describes also a firing-mechanism comprising a hammer 152 adapted to be cocked by the opening of the breech when the hammer bears against the bottom of the breech-bolt preferably by means of a roller 156, and to strike the rear end of the firing-pin 80 when released by a sear 159 after the closing of the breech. The hammer is pivoted at 139 to a frame 150 secured on a platform 3a of the stock by bolts 151. The sear 159 is also pivoted on the same frame at 160, and the hammer and the sear have a common spring 161, which is arranged on a rod 162 pivoted at one end to the hammer at 164 and slidable at the other end in a lug 165 on the sear. The spring is confined by a cage 166 which limits its expansion, thereby allowing a slight freedom of backward movement to the hammer before the spring comes into action, the spring taking its seat at the rear end against the rear wall of the cage and at the front end against a flange 170 on a sleeve 169, which transmits the pressure to the hammer but whose movement is limited by the front wall of the cage. The sear has a depending arm 172, by means of which it is operated by a pawl 174 pivoted at 175 to a trigger 177. The pawl 174 becomes disconnected after a shot is fired and remains disconnected until the trigger is returned forward. Moreover, the pawl 174 is put out of action when the breech is not closed by means of a lever, which is deflected by the gas fork 28 and rocks the pawl 174 away from the arm 172 of the sear. Further safety is provided by a transversely sliding pin 193, which in one position leaves the pawl 174 and the sear 159 free, and in another position deflects the pawl 174 away from the arm 172 of the sear and blocks the downward path of a lug 198 on the sear 159. This subject-matter does not appear in the Specification as accepted.